Rescue workers continued the search for hundreds of missing people on Indonesia's tsunami-hit Mentawai islands. The death toll could rise to around 600, officials said.

The death toll from Monday's 7.7-magnitude earthquake was at 394, while 312 people were listed as missing Ade Edward, head of the Regional Disaster Management Agency in the West Sumatra province, told the Deutsche Presse-Agentur.

Mount Merapi erputed again for 21 minutes Saturday, followed by more than 350 volcanic tremors and 33 ash bursts, the Canadian Press said.

Rescue workers hoped to airdrop aid, but storms made it too dangerous.

The wife of this year's Nobel Peace Prize winner, Liu Xiaobo, has been placed under house arrest after meeting with her husband Sunday who is serving an 11-year prison sentence in northeastern China.

After the visit, Liu Xia was taken back to Beijing and placed under house arrest, a human rights group told the New York Times.

"Liu Xia is in her Beijing apartment but is no longer allowed to leave her apartment or to have anybody in and her phone has been desetroyed," human rights group Freedom Now's correspondent Beth Schwanke told ABC News.

Mr. Liu was active in the June 4, 1989 movement where nonviolent pro-democracy demonstrators gathered and Chinese troops then killed many.

U.S. officials apologized Friday for a study from 60 years ago that deliberately infected hundreds of people with sexually transmitted diseases in Guatemala.

The apology was prompted after a Wellesley College historian discovered the archived documents. The documents outlined the experiments that tested whether penicillin could prevent infection with sexually transmitted diseases, the Associated Press said.

At least 1,500 people participated in the study.

"No matter how much of a superpower it is, the United States cannot do this kind of experimentation," Nery Rodenas, the chief of the human rights office at the archbishop of Guatemala's office, told the Agence France-Presse.